<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <input type="button" value="播放">
</body>
<script>
    let input = document.querySelector('input');
    input.onclick = function()
    {
        if(input.value === '播放')
        {
            input.value = '停止';
        }
        else
        {
            input.value = '播放'
        }
    }
</script>
</html>